1. Field of the Invention
The present invention relates to monitoring apparatus and more particularly to an apparatus of monitoring electric power of a motor vehicle""s battery and method thereof so as to issue an alarm if the power is lower than a predetermined level prior to starting the engine.
2. Description of Related Art
It is known that a driver has to start the engine of an automobile prior to starting it. Also, for successfully starting the engine, there must be sufficient power in the battery. In practice, however, there is no way for the driver to know the power level of the battery prior to starting the engine. It is often that the driver knows the battery low only when the start fails. Alternatively, the battery may be already damaged before a next start even it is successful in this start.
Moreover, many different factors such as ambient temperature, charging conditions and time, and load discharge all can affect a useful life of battery Thus, it is complicated. A conventional battery (e.g., NP battery) has the following characteristic curves regarding discharge time versus discharge voltage, ambient temperature versus available power of battery, and storage time versus available power of battery as shown in FIGS. 12 to 14 respectively. Thus, for ensuring a successful start of the automobile it is desirable to monitor the available power of battery in a long time basis in order to overcome disadvantages that may be caused by the above factors.
It is an object of the present invention to, in a motor vehicle, provide an apparatus of monitoring its electric power and method thereof in a long time basis. The apparatus comprises a monitor and alarm device parallel connected to both a battery to be measured and a starting motor of the motor vehicle wherein a single loop technique the starting motor is taken as a load for forming an outer loop sampling circuit, 1/t second is set as a sampling time interval during discharging, a voltage curve is formed by connecting a plurality of continuous voltage values each sampled in 1/t second, a voltage measured at the parallel terminals is dropped significantly temporarily during an engine starting period, thus forming a lowest point of the voltage curve, a minimum voltage of the voltage curve as obtained at the lowest point is compared with a predetermined alarm value for determining a status of the battery to be measured, and an alarm is issued in time if the status of the battery to be measured is abnormal.
It is another object of the present invention to provide an apparatus of monitoring motor vehicle""s electric power and method thereof. A monitor and alarm device of the apparatus is directly parallel connected to both a battery to be measured and a starting motor of the motor vehicle wherein a double loop technique is employed to monitor an available power of a current source to be measured in a long time basis, the starting motor is taken as a load for forming an outer loop sampling circuit, an inner loop sampling circuit is formed by utilizing an internal load of the monitor and alarm device, and alternatively perform different monitoring modes by suitably dividing time into a plurality of time intervals.
It is a further object of the present invention to provide an apparatus of monitoring motor vehicle""s electric power and method thereof. A monitor and alarm device of the apparatus takes any point of the voltage curve during an engine starting as a battery measurement point. That is, a voltage value at any point of a curve section from the engine starting point to an alternator charging point is taken as a battery measurement point. Hence, it is possible of determining a status of the battery to be measured and issuing an alarm in time if the status of the battery to be measured is abnormal.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.